The use of 了 (the perfective aspect particle and the modal particle)The Chinese language does not have tenses; instead, there are aspects, which indicate the stages of event. The focus of the first part of this chapter will be on the perfective aspect, which is indicated with the perfective aspect particle 了 (le) immediately following the verb.Since 了 can also function as a modal particle, which appears at the end of the sentence, the use of 了 as a modal particle will be the focus of the second part of this chapter.

A. A progressive aspect particle 了The perfective aspect is used to indicate the completion of the action; it is however equivalent to the past tense in English. The completion of an action may have occurred in the past, but it may occur in the future as well. Also, a past event may or may not need a perfective aspect particle 了.

1. Habitual past eventsA past event which is habitual does not take the perfective particle 了.我小时候每天早上都和一杯牛奶。Wǒ xiǎo de shíhou měi tiān zǎoshang dōu hē yì bēi niúnǎi.When I was very young, I drank a glass of milk every morning.

我在中国的时候，每星期都去看（一场）中国电影。Wǒ zài Zhōngguó de shíhou, měi xīngqī dōu qù kàn (yì chǎng) diànyǐng.When I was in China, I went to a Chinese movie every week.

2. Quantified past eventsA quantified past event (i.e., the object of the verb includes either a number or 很多/不少) usually takes the perfective particle 了.昨天我跟妈妈去外面吃饭。我们叫了一条鱼跟一只烤鸭。Zuótiān wǒ gēn māma qù wàimiàn chī fàn. Wǒmen jiào le yì tiào yú gēn yì zhī kǎoyā.Yesterday my mother and I went out to eat. We ordered a fish and a roast duck.

我在中国的时候，认识了不少中国朋友。Wǒ zài Zhōngguó de shíhou, rènshi le bù shǎo Zhōngguó péngyou.When I was studying in China, I made many Chinese friends.

(b) When the object of the verb is a proper noun or pronoun.李：昨天我在路上遇见了老王。Lǐ: Zuótiān wǒ zài lù shàng yùjiàn le Lǎo Wáng.张：真巧！我今天也在路上遇见了他。Zhāng: Zhēn qiǎo! Wǒ jīntiān yě zài lù shàng yùjiàn le tā.Li: I ran into Lao Wang on the street yesterday.Zhang: What a coincidence! I also ran into him on the street today.

(c) When the object of the verb is 什么/哪 or the answer to a question with 什么/哪王：下午我去你家找你，你妈说你去超级市场买东西（了）。你买了什么？Wáng: Xiàwǔ wǒ qù nǐ jiā zhǎo nǐ, nǐ mā shuō nǐ qù chāojíshìchǎng mǎi dōngxi (le). Nǐ mǎi le shénme?李：我买了水果、面包跟牛奶。Lǐ: Wǒ mǎi le shuǐguǒ, miànbāo gēn niúnǎi.Wang: In the afternoon I went to your house to see you; your mother said you had gone to the supermarket to buy some things. What did you buy?Li: I bought fruit, bread and milk.

4. Two verbs: One action after anotherWhen a situation includes two actions, and the second action takes place immediately after the completion of the first, the aspect particle 了 is used to indicate the completion of the first action even if the object of the verb is not quantified or does not have a modifier. These two actions may or may not be past events.

(a) The use of 就It should be noted that 就 or another adverb is frequently used to link the two actions. Without such adverb, the sentence may not sound correct.我爸爸每天吃了饭就吃胃药。 (吃胃药 is a habitual event. 就 is necessary)Wǒ bàba měitiān chī le fàn jiù chī wèiyào.My father takes acid-reducing medicine right after dinner every day.

明天咱们下了课一起去看场电影，怎么样？(看电影 is a future event.)Míngtiān zánmen xià le kè yì qǐ qù kàn chǎng diànyǐng, zěnmeyàng?How about if we go to a movie after the class tomorrow?

(b) Modal particle 了 instead of perfective aspect particle 了In a simple sentence, the perfective aspect particle 了 is not used if the object of the verb is not quantified or does not have a modifier; instead, modal particle 了 is used at the end of the sentence.

Mr. Wang bought a car. (This is a simple sentence.)王先生买车了。(了 is a modal particle since it appears at the end of the sentence.)Wáng xiānsheng mǎi chē le.王先生买了一辆车。(了 is the perfective aspect particle since it follows the verb.)Wáng xiānsheng mǎi le yí liàng chē.

An optional perfective aspect particle and a necessary modal particle can be used together in a simple sentence.王先生买了车了。(=王先生买车了。)Wáng xiānsheng mǎi le chē le.(Incorrect: 王先生买了车。)

5. Two verbs: One indicating purposeWhen a simple sentence has two verbs and the second verb indicates the purpose of the first verb, such as 来, 去 or 用, the perfective aspect particle 了 follows the second verb if it is a past event.

下午我去超级市场买了一些水果和面包。Xiàwǔ wǒ qù chāojíshìchǎng mǎi le yì xiē shuǐguǒ hé miànbāo.I went to the supermarket to buy some fruit and bread in the afternoon.(Incorrect: 下午我去了超级市场买一些水果和面包。)